期刊
APPLIED PHYSICS LETTERS
卷 112, 期 1, 页码 -出版社
AMER INST PHYSICS
DOI: 10.1063/1.5009617
关键词
-
资金
- NSF [EAR1524078]
- DOE/NNSA [DE-NA0002907]
- Shenzhen Peacock Team Project [KQTD2016053019134356]
- Guangdong Innovative & Entrepreneurial Research Team Program [2016ZT06C279]
Compressional and shear wave velocities of polycrystalline niobium have been measured at simultaneously high pressures and temperatures up to 5.8 GPa and 1073 K, respectively, using ultrasonic interferometry in conjunction with synchrotron x-ray techniques. An anomalous pressure-induced softening behavior in the phonon velocities, probably owing to the topological change in the Fermi surface, has been observed at similar to 4.8 GPa during cold compression, which is supported by the elasticity data from our first-principles calculations. In contrast, both the bulk (B-S) and shear (G) moduli increase with pressures but decrease with temperatures upon compression at extreme P-T up to 5.8 GPa and 1073 K. Using finite strain equation-of-state approaches, the elasticity of bulk and shear moduli and their pressure and temperature dependences are derived from the directly measured velocities and densities, yielding B-S0 = 174.9(3.2) GPa, G(0) = 37.1(3) GPa, partial derivative B-S/partial derivative P = 3.97(9), partial derivative G/partial derivative P = 0.83(5), partial derivative B-S/partial derivative T = -0.064(7) GPa/K, and partial derivative G/partial derivative T = -0.012(3) GPa/K. On the basis of the current thermoelasticity data, Debye temperature and the high-pressure melting curve of Nb are derived. The origin of the anomalies in shear behavior at high pressure might be attributed to the progressive s-d electron-transfer-induced topological changes of the Fermi surface upon compression. Published by AIP Publishing.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据